[18a-E204-1~11] 3.1 Basic optics and frontier of optics

▼ [18a-E204-7] Optical Spin-transfer Torque Calculated in Relation with Optical Chirality

〇(D)Anan Wu¹, Yoshito Tanaka^1,2, Ryoma Fukuhara¹, Tsutomu Shimura¹ (1.IIS, the Univ. of Tokyo, 2.JST PRESTO)

Keywords:optical torque, optical chirality

Light-matter interaction can induce optical torque acting on the matter due to the transfer of angular momenta carried by the light, including the spin angular momentum (SAM) and the orbital angular momentum (OAM). The Maxwell stress tensor method is extensively used in calculating the optical torque based on the transfer of total angular momentum of SAM and OAM. In other words, this method is unable to separate the optical torques produced by the SAM and the OAM. Here, we introduce an important quantity, that is optical chirality, and reveal its relation to the SAM. Based on the relation, we propose a method to calculate the optical torque produced by the SAM separately from that by the OAM.